Submersible multi-parameter sonde having a high sensor form factor sensor

ABSTRACT

Provided are multi-parameter sonde systems having a unique form-factor, wherein the plurality of sensors are arranged in a tight-fit configuration. This provides a single distal sensing surface and minimal separation distance between adjacent sensors. The sensors may be pie shaped with an interlocking feature to tightly hold the sensors together, with a sensor guard disposed over the outer surface of the interlocked sensors. Sensor-guards disclosed herein may have an integrated sensor storage and sensor guard configuration, thereby avoiding a need for a separate storage cup and that are configured to minimize unwanted biological growth. Also provided are uniquely shaped individual sensors having interlocking features to hold several sensors together in a sonde.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority of U.S. ProvisionalApplication Ser. Nos. 62/077,528 and 62/077,627 filed Nov. 10, 2014, and62/115,466 and 62/115,593 filed Feb. 12, 2015, the disclosures of whichare each individually incorporated by reference to the extent notinconsistent herewith.

BACKGROUND OF INVENTION

Provided herein are water quality instruments containing multiplesensors for measuring a plurality of water-related parameters. Thesensors are uniquely configured to have an extremely high form factor sothat they may be contained within a housing that minimizes dead spacebetween sensors and within the housing, with the individual sensor endsforming a single continuous sensing surface. This provides a number offunctional benefits in the field of multi-parameter sondes and relatedsensing methods.

Conventional multi-parameter sondes use a plurality of round or circularsensors that are aligned in a longitudinal direction. With thecircular-based geometry, there is substantial dead space or void volumebetween the sensors, resulting in a number of disadvantages. Forexample, this dead space must be filled with a fluid in order to ensureappropriate sensor coverage and, therefore, significantly increases theamount of fluid required during sampling. Larger fluid volumes tend torequire longer testing times, particularly for low-flow sensingapplications, such as sampling from well water. In addition, manysensors require periodic calibration, including prior to dataacquisition. This requires a calibration solution and certaincalibration solutions are expensive, such as in the $100's/L range.

The large dead space also suffers from the tendency for biologicalgrowth to occur in the dead space and on and over the sensors. This isparticularly problematic for long deployments, where the large availablesurface area in long term contact with biologically active waterprovides a large surface for biological growth, such as from plants,algae and/or animals that anchor to a wetted surface. Multi-parametersondes with spaced-apart sensors suffer from significant biologicalgrowth which must be cleaned to avoid sensor fouling and maintainsensitivity. The open spaces between sensing surfaces makes it difficultto effectively and efficiently automate cleaning, such as with abrush-type wiper.

In view of these limitations, there is a need in the art forfundamentally different sonde configurations and related components thatavoid the large open spaces between sensors. Provided herein are sensorswith a fundamental change in structure that address the limitations ofconventional sonde sensors, and sondes that incorporate the sensorsprovided herein with additional components that provide fundamentalbenefits and attendant improved sonde reliability, durability, andsensitivity.

SUMMARY OF THE INVENTION

Conventional multi-parameter sondes generally incorporate round-typesensors that extend from a body. This results in substantial spacebetween sensors that, during use, is filled with a liquid such as awater sample, a calibration fluid, or a storage fluid. Provided hereinare sensors that address this limitation by specially shaped sensorsthat facilitate tight-fit and an attendant tightly packaged multi-sensorconfiguration. Instead of the uniformly rounded side walls found inconventional sensors, side walls of the instant sensor lie insubstantially or entirely a single plane. In this manner, differentsensors may tightly contact each other, thereby minimizing andsubstantially avoiding dead space. Furthermore, the distal end of thesensors, which are adjacent to each other, form a single sensing surfacein a generally continuous and flat plane. Accordingly, a compositesingle sensor surface is formed from a plurality of independent sensors.This aspect may then be leveraged into an improved configuration for anumber of other sonde components. For example, a unique interlockingconfiguration may be employed from a single central support to reliablyanchor the sensors in an independent manner without sacrificing theability to remove and replace individual sensors.

The tightly-fitting plurality of sensors also provides improvedruggedness in that the sensors are more impact resistant compared to themore widely spaced-apart sensors in conventional sondes. The uniqueouter shape of the combination of sensors in the tight-fit configurationfacilitates a tight fit sensor guard that further constrains the sensorsand prevents, for example, sensor deflection during an impact event. Incontrast, conventional sondes having dead space between sensors, sufferfrom substantial sensor deflection during an impact event, even for whenthe sensors are positioned within a guard-type structure.

Provided herein are multi-parameter sondes, and specific componentsthereof, including sonde sensors, sensor guards having an integratedsensor storage configuration, wipers that prevent unwanted build-up overthe sensor and in the volume between the sensor sensing surface and theguard. Also provided are methods of using or making any of the sondesand components herein.

In an embodiment, provided is a multi-parameter sonde comprising aplurality of independent sensors each having a distal sensing surfaceand a proximal end. In this manner, the sensors may generally bedescribed as longitudinally extending in that the longest dimension isin the longitudinal direction extending between the ends. A baseoperably connects to the proximal end of each of the sensors. Adjacentdistal sensing surfaces contact each other to form a continuous distalsensing surface comprising the plurality of independent sensors. In thismanner, substantial gaps or empty spaces between adjacent sensors areavoided.

The base communicates with the sensors, such as by providing commands toand receiving data from the sensors, and contains other relevantelectronics such as for displaying information, recording readings, andoutputting readings, as well as related components including a powersource and connections thereto, including as provided by U.S.Provisional Patent Application by Duane McKee titled “Integrated UserInterface for Status and Control of a Submersible Multi-Parameter Sonde”filed Nov. 10, 2014.

Each of the plurality of independent sensors comprise an inner corneredge and a pair of side surfaces extending from the inner corner edge.The sides end at an outer edge and define a plane. The planes areseparated from each other by a side angle. An outer facing surfaceconnects the pair of side surfaces at the outer edge, thereby forming athree-sided sensor housing. Accordingly, adjacent sensors may have theirsides in intimate contact with each other, with an external surfaceformed by the plurality of outer-facing surfaces. For example, in usethe side surfaces of adjacent sensors are in substantially continuouscontact or continuous contact.

The outer surface has any desired shape. For example, if a straight-edgeouter surface is desired, the outer surface may comprise a portion thatis straight-edged or may be entirely straight-edged (e.g., trianglecross section). In an aspect, the plurality of sensors form an outersurface having circular cross-section. In this manner, each individualsensor has a curved outer surface that forms part of a circle, with alength that extends between the side outer edges defined by the sideangle and the length of the side from the inner corner edge, alsoreferred herein as a radial dimension or distance.

The multi-parameter sonde provided herein is compatible with any numberof individual sensors. For example, the base may operably connectbetween 2 and 12 sensors and the side angle may be correspondinglyselected such as from a range that is greater than or equal to 30° andless than or equal to 180°.

In one embodiment, the base operably connects four sensors, each sensorhaving a side angle of 90° and an outer facing surface with a curvaturecorresponding to one-quarter of a circle so that the plurality ofsensors form an outer surface with a cross-section that is substantiallycircular. Similarly, any number (n) of sensors may be employed, with theresultant external surface formed by the plurality of outer-facingsurfaces having a circular cross-section. In this manner, the sum of then side sensor angles is about 360°.

In many applications, not all the available sensors are required. Sothat for a sonde having “n” sensors, the application requires a numberof sensors less than “n”. In such a situation, rather than having anunneeded and expensive sensor in the sonde, a sensor blank may be used,wherein the sensor blank has an external shape that corresponds to anexternal shape of the sensor being replaced. For example, for afour-sensor configuration, the sonde may have one sensor blank and threesensors, two sensor blanks and two sensors, or three sensor blanks andone sensor. The sensor blank has a surface shape corresponding to theto-be-replaced sensor, with the internal volume devoid of any expensivesensing and electronic circuitry associated with the sensingfunctionality.

Any of the multi-parameter sondes provided herein may further comprise asensor-guard having a sensor receiving volume and a sample sensingvolume, wherein the plurality of sensors occupy substantially the entirevolume of the sensor receiving volume. The sensor receiving volumecorresponds to that portion of the sensor guard that extends from thebase to the distal sensing surface. In this aspect, “substantially theentire volume” refers to at least 90%, at least 95% or at least 99% ofthe sensor receiving volume that is physically occupied by the pluralityof sensors. Accordingly, the sondes may be described in terms of deadspace or void volume within the sensor guard that is less than 10%, lessthan 5% or less than 1% of the sensor receiving volume portion of thesensor guard. Of course, there is another portion of the sensor guardthat has a liquid-containing volume but that is not considered a deadspace or void volume because that portion serves an important functionalrole of allowing the sensor(s) to measure a water parameter. Thatportion is also referred herein as the sensing volume and may be betweenabout 30 mL and 100 mL. In an aspect, the dead space or void volume isselected from a range that is between about 1% and 10%, or is about 5%,with a corresponding sensor volume between about 99% and 90% of thepossible volume, or about 95%.

In an embodiment, to ensure the distal sensing surfaces form acontinuous sensing surface a distal insert surface may span between anyopen gaps at the distal end, such as a cover with openings for thesensor ends.

Any of the multi-parameter sondes may further comprise a central supportextending from the base that independently releasably connects each ofthe plurality of sensors. In this manner, the sensors may reliablyconnect at a center edge, to ensure sensors are tightly fit against acentral axis of the sonde. In this manner, each of the plurality ofsensors comprises a corner edge extending from the distal sensingsurface and partway toward the proximal end, the corner edge shaped toreceive at least a portion of the central support or a drive shaftextending therefrom; a pair of side surfaces that extend from the corneredge and that are separated from each other by a side angle; and anouter facing surface that connects the pair of side surfaces at an outeredge of each of the side surfaces, thereby forming a three-sided sensorhousing.

In an aspect, each of the plurality of sensors further comprise: a topportion of each of the pair of side surfaces having a top width; abottom portion of each of the pair of side surfaces having a bottomwidth, wherein the bottom width is less than the top width to therebyform a bottom notch and a notch end surface; a tongue connected to thenotch end surface and longitudinally extending partway down the notch; afastening member to fasten the sensor to the base; wherein incombination, the plurality of sensors form: a top sensing volume havingwith a central orifice for receiving a drive-shaft extending from thecentral support; and a bottom portion having a central receiving volumefor receiving the central support and a drive shaft motor positionedtherein; the central support having a plurality of grooves to operablyreceive the tongues and independently secure each of the sensors to thecentral portion. In this manner, the unique geometry of each sensorallows for an important functional benefit related to sensor connection,removal and replacement, without sacrificing the tight-fit and high formfactor advantages described herein.

The invention is compatible with other fastening means. For example, thecentral support may support the tongue and a receiving passagepositioned in the sensor. Magnetic connections or set screws may beused, so long as they do not interfere with sensor operation. Snap-fitor quick-release connectors may be similarly incorporated in the centralsupport and in inner facing surface of the sensors.

In an aspect, each of the plurality of sensors are tightly held againstthe central shaft, and a sensor guard is tight-fitted around an outeredge formed by the outer-facing surfaces of the sensors. This providesthe functional benefit of the sonde sensors being able to withstandimpact force without deflection and associated risk of damage. Thisbenefit is achieved by the high form factor sensors that facilitatetight packing within the guard.

The outer-facing surface of the sensors may be curved so that theplurality of sensors in combination form a circular cross-section. Theplurality of sensors may form a continuous outer-facing surface that isin a tight fit with an inner-facing surface of the sensor guard. Themulti-parameter sonde may have a sensor side wall in continuous contactwith an adjacent sensor side wall, including in a similar tight-fitconfiguration. In this manner, the sensor guard proximal portion, alsoreferred herein as sensor receiving volume, is substantially entirelyfilled with the plurality of sensors.

In an aspect, each of the sensors: extend a longitudinal distance thatis greater than or equal to 5 cm and less than or equal to 50 cm; have aradial dimension that is greater than or equal to 1 cm and less than orequal to 10 cm; and wherein the plurality of sensors in combination havea void volume that is less than or equal to 10 mL, or less than or equalto 1 mL, or between about 0.5 mL and 5 mL. The separation distance ofadjacent surfaces, and corresponding quantification of “tight-fit” maybe determined by estimating the surface area available for wet contactbetween adjacent surfaces and providing fluid to the system until it isfilled to the sensor surface (e.g., the void volume). In an aspect wherethe sensor radial dimension is about 2 cm and sensor length is about 12cm, there is a total surface area available for water contact associatedwith the sensor guard and the adjacent sensor surfaces that is about 240cm². With an empirically determined void volume that is less than about5 mL, or less than about 1 mL, an average separation distance may becalculated. The volume that is meant to hold liquid and for sensing bythe sensors may be about 45 mL. Accordingly, in an aspect “tight-fit”refers to surfaces that are separated from each other by a distance thatis less than 2 mm, less than 1 mm, less than 0.5 mm, or less than 0.2mm. In an aspect, the gap between the sensors and the sensor guard isless than 0.2 mm. Similarly, a “continuous surface” may correspond toindividual surfaces that are separated from adjacent surfaces by adistance that is less than about 2 mm, less than 1 mm, less than 0.5 mm,or less than 0.3 mm. In an aspect, the separation distance or gapbetween sensors is about 0.25 mm.

In another aspect, the void volume may be functionally described, suchas having at least one dimension associated with a sensor that issufficiently small that biological growth is substantially constrained.In this aspect, the dimension may be the separation distance betweenadjacent surfaces, such as, for example, less than less than 1 mm, lessthan 0.5 mm, or less than 0.3 mm. In this context, “substantiallyconstrained” refers to no biological growth is observable to the nakedeye between adjacent surfaces after a time period, such as a time periodof up to one month, or longer than one month. Alternatively, anyobservable growth may be defined as minimal in that there is nomeasurable impact on sensor or sonde performance. A particularlybeneficial aspect of the specially configured sensors and sensor guardsis that the air-tight seal between the sensors and guard and thedeployment of the sonde into the water results in formation of an airpocket in the small volume between the sensor and guard inner surface.Such an air pocket further inhibits the ability for biological growthand corresponding fouling around the sensor. Instead, even afterlong-term deployment, biological growth is not observable on surfacescorresponding to the air pocket, but instead is confined only to thewetted surface area, such as at the distal-most portion of the sensor,including the distal-most 10%, 5% or 1% or less length.

In an embodiment, the invention further relates to wipers, as thesubstantially continuous distal sensing surface provides a well-definedsurface without substantial empty spaces that may be cleaned effectivelywith a wiper, such as a wiper connected to a distal end of the driveshaft for rotably brushing each of the distal sensing surfaces.

The multi-parameter sonde may further comprise a sensor guard thatconnects to the base and surrounds the plurality of sensors in atight-fit configuration, the sensor guard having a sample sensing volumeformed by a distal portion of a sensor guard sidewall, a sensor guardtop surface, and the plurality of distal sensing surfaces, wherein thewiper is positioned within the sample sensing volume. In this aspect,the wiper may comprise a central wiper body connected to the driveshaft, the central wiper body having a lower surface that faces thedistal sensing surfaces and an upper surface that faces the sensor guardtop surface; a first wiper connected to the lower surface for cleaningthe plurality of sensing surfaces; and a second wiper connected to theupper surface for cleaning an inward-facing surface of the sensor guardtop surface. In this manner, a single wiper system with the double wipersides simultaneously cleans both the sensors and the sensor guard cap,including by pushing out debris from the sensor guard cap area. Incontrast, conventional systems suffer from the disadvantage of havingdebris that can build up on the top surface of the sensor guard, whichcan cause reading errors. This can be avoided herein by use of thedouble wiper configuration. In an aspect, the wiper comprises a brush,such as a pair of brushes.

The unique configuration of the sensors permit positioning of thecomponents required to move the brush, including motor, slip clutch anddrive shaft, within volumes formed by the tight-fit connection of theplurality of sensors. For example, the multi-parameter sonde may furthercomprise a motor and a slip clutch operably positioned in the centralsupport and connected to the drive shaft to provide rotational motion ofthe drive shaft and the wiper connected thereto. The slip clutch ensuresthat should the brush be manually moved, there is not damage to delicatecomponents, such as a gearbox, and associated costly repair anddown-time.

In an embodiment, the multi-parameter sonde further comprises a positionsensor operably connected to the motor to ensure wiper storage at awiper stored position that does not adversely affect a sensor function.For example, the wiper storage position may be at a position that is180° from a sensor that is actively measuring a parameter.

Any of the multi-parameter sondes may further comprise a sensor guardthat surrounds the plurality of sensors and connects to the base. Asdiscussed, this unique configuration provides a robust, rugged andimpact-resistant sonde.

The sensor guard may have a sensing end comprising a fluid opening or aplurality of fluid openings and a covering end that is liquid tight. Thesensing end and the covering end may be separated from each other by acentral sensor guard portion. A cap configured to connect to both thesensing end and the covering end is connected, as desired, at either thesensing end or the covering end. Similarly, the sensing end and thecovering end are each configured to connect to the base to provideeither: (1) a sensor guard configuration for the sensing end alignedwith the distal sensing surfaces and the covering end connected to thebase; or (2) a sensor storage configuration for the covering end alignedwith the distal sensing surfaces and the sensing end connected to thebase. The sensor guard is configured to reversibly change between thesensor guard configuration and the sensor storage configuration, such asby switching the cap to the other end of the guard and connecting theopen-ended portion of the guard to the base. Any of the connections maybe by matching threads and the connection made by a screwing motion ofthe sensor guard into/out of the base and the cap into/out of the sensorguard ends.

The cap may have an internal surface that opposably faces the continuoussensing distal sensing surface and is separated from the continuoussensing distal sensing surface by a sample distance that is greater thanor equal to 1 cm and less than or equal to 10 cm.

The multi-parameter sonde may further comprise a rotatable brush thattraverses the sample distance for simultaneous cleaning of thecontinuous sensing distal surface and the cap internal surface.Simultaneous cleaning refers to the rotation of one drive shaft cleansboth surfaces.

In another embodiment, provided is a sensor configured for use in amulti-parameter sonde, including any of the multi-parameter sondesdescribed herein. The sensor comprises an inner corner edge with a pairof side surfaces extending from the inner corner edge and ending at anouter edge. The side surfaces define a plane and the planes areseparated from each other by a side angle. An outer facing surfaceconnects the pair of side surfaces at the outer edge, thereby forming athree-sided sensor housing. At one end of the sensor housing there is adistal sensing surface, having the active sensing elements that interactwith the fluid sample. At the other end there is a proximal end, whereinthe pair of side surfaces and the outer-facing surface longitudinallyextend between the proximal and the distal sensing surface to form asensor housing. A sensor is disposed within the sensor housing andhaving an active sensing end positioned at the distal sensing surface.

Depending on the number of sensors to be supported by the sonde, theside angle is selected from a range that is greater than 30° and lessthan or equal to 180°. In an embodiment, the plurality of sondes have aside angle sum that corresponds to 360°, thereby ensuring the sensorguard sensor volume is substantially occupied. In an embodiment, allangles may be the same, with four sensors with 90° side angle, sixsensor with 60°, etc. Alternatively, the sensors may have different sideangles, such as five sensors of 60° and two with 30°, etc., so long asthe total of the side angles is 360°.

In an aspect, any of the sensors have a top portion of each of the pairof sides having a top width; a bottom portion of each of the pair ofsides having a bottom width, wherein the bottom width is less than thetop width to thereby form a bottom notch and a notch end surface betweenthe top portion and the bottom portion; a tongue connected to the notchend surface and longitudinally extending partway down the notch; and afastening member connected to the proximal end for operably connectingthe sensor to a multi-parameter sonde.

The multi-parameter sonde may have a central support having a pluralityof grooves for connecting to a plurality of tongues from a plurality ofsensors. The plurality of sensors connected to the multi-parameter sondeforms a closed outer surface that is circular in cross-section.

Another embodiment provided herein is a submersible sonde having anintegrated storage cap. This sensor guard is unique in that it can beflipped around and used as storage cup. Conventional instruments have asensor guard and a separate storage cup. Accordingly, this aspect of theinvention completely eliminates a separate part and solves a common userissue where the user in the field retrieves their sonde, but forgets thestorage cup. Without a storage cup installed, pH probes can dry outwhich can cause damage to the sensor. With this embodiment, the userdoes not have to worry about keeping track of and bringing a storage cupbecause the storage cup is integrated with the instrument.

The submersible sonde may comprise a base portion and a sensor portionhaving a proximal end connected to the base portion and a distal sensorend for sensing a water parameter. A reversible sensor guard comprises asensing end comprising a fluid opening; a covering end that is liquidtight, the sensing end and the covering end may be separated from eachother by a central sensor guard portion; a cap that connects to eitherof the sensing end or the covering end; and the sensor guard isreversibly connected to the base to provide: (1) a sensor guardconfiguration for the sensing end aligned with the distal sensingsurfaces and the covering end connected to the base; and (2) a sensorstorage configuration for the covering end aligned with the distalsensing surfaces and the sensing end connected to the base. The sensorguard is configured to reversibly change between the sensor guardconfiguration and the sensor storage configuration.

Also provided is a method of monitoring one or more water parameters,the method comprising the steps of: immersing any of the multi-parametersondes provided herein with a sensor guard into water, wherein themulti-parameter sonde is in the sensor guard configuration; forming anair-pocket between an outer-facing surface of the sensors and aninner-facing surface of the guard, wherein the air-pocket forms over 90%or greater of a longitudinal distance of the sensors extending from thebase, and less than 10% or less of the longitudinal distance from thedistal sensing end is wetted; wherein observable biological growth isprevented in the air pocket and is confined to a biological growth areacorresponding to the wetted distal sensor end. In this manner, even forlong term monitoring, such as on the order of greater than 30 days,biofouling associated with unwanted biological growth is avoided, withminimal unwanted biological growth between the sensor outer surfaces andthe guard inner-surface. This provides the functional benefit of bothincreased sonde longevity without active maintenance and makesmaintenance much more convenient and user-friendly, with minimalcleaning.

Without wishing to be bound by any particular theory, there may bediscussion herein of beliefs or understandings of underlying principlesrelating to the devices and methods disclosed herein. It is recognizedthat regardless of the ultimate correctness of any mechanisticexplanation or hypothesis, an embodiment of the invention cannonetheless be operative and useful.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a top perspective view of a multi-parameter sonde with asensor guard in a sensor guard configuration. 1B is a bottom perspectiveview thereof. 1C is a side view thereof.

FIG. 2A is a side view of the multi-parameter sonde of 1A with thesensor guard removed to show the plurality of sensors that are in anadjacent configuration and a cleaning brush that are normally confinedwithin a sensor guard during use. 2B is a perspective view thereof.

FIG. 3A-3J are various views of an individual sensor that has beenremoved from the multi-parameter sonde, such as one of the sensorsillustrated in FIG. 2B.

FIG. 4A-4B are illustrations of a base of the multi-parameter sonde,with the sensor guard, plurality of sensors, and central drive shaftremoved, from a side and perspective view, respectively.

FIG. 5A-5B show the multi-parameter sonde in a sensor storageconfiguration. 5C is a sectional view of the distal sensing surface andcap, illustrating the sensing volume and sensing separation distancebetween sensing surface and sensor guard cap inner-facing surface.

FIG. 6A-6D are illustrations of the sensor guard. FIGS. 6B-6C illustratea plurality of single fluid openings. Another example is provided inFIGS. 6A and 6D, with each of the openings of FIGS. 6B-6C provided astwo separate openings separated by a separation distance.

FIG. 7A-7D are illustrations of a wiper that may be connected to themulti-parameter sonde for cleaning to improve sensor reliability andincrease sensor longevity.

FIG. 8 is a three-dimensional rendering of the multi-parameter sondewith the sensor guard removed.

FIG. 9 illustrates the independent removal of one of four sensors fromthe multi-parameter sonde of FIG. 8, with a corresponding centralsupport member that removably connects each of the sensors.

FIG. 10 illustrates one of the sensors from the multi-parameter sonde ofFIG. 8 in a removed configuration.

FIG. 11 is a schematic illustration illustrating the inner corner edgeof a removed sonde of FIG. 10.

FIG. 12 is a close-up view of the continuous distal surface of themulti-parameter sonde of FIG. 8 with a wiper.

FIG. 13 shows the continuous distal surface of the multi-parameter sondeof FIG. 12 with the replaceable wiper removed, to better illustrate thatthe tight-fit between adjacent sensors leaves no observable spacesbetween the sensors, thereby improving wiping action with the wiper ofFIG. 12.

FIG. 14 is a visual process flow summary summarizing the steps forchanging a sensor guard from a sensor-guard configuration (top panel) toa sensor-storage position (bottom panel).

FIG. 15 is a close-up view of the distal sensing surface and sensingvolume with sensor guard and wiper.

FIG. 16 longitudinally-directed view from the distal sensing surfacetoward the sonde base illustrating a cross-section outer surface of theplurality of sensors that is circular.

FIG. 17. Internal view of central support section containing motor andrelated components for turning a drive shaft to which a wiper isconnected.

FIG. 18. Schematic illustration comparing the increased distal sensorsurface area available to a pie-shaped sensor compared to an equivalentcircle-shaped sensor.

DETAILED DESCRIPTION OF THE INVENTION

In general, the terms and phrases used herein have their art-recognizedmeaning, which can be found by reference to standard texts, journalreferences and contexts known to those skilled in the art. The followingdefinitions are provided to clarify their specific use in the context ofthe invention.

“Sonde” refers to a water quality monitoring instrument.“Multi-parameter” refers to a sonde having multiple independent separatesensors for providing multiple water parameter values.

“Independent sensors” refers to the ability to insert or remove a sensorwithout affecting other sensors. For example, one of the sensors may beremoved and replaced with a sensor blank. Similarly, a user in the fieldmay simply remove one independent sensor and replace it with another ofthe same or different sensor, without affecting the other sensors.“Sensor blank” refers to an equivalently shaped object that is used inplace of a sensor. It is useful if the user does not need or have asensor to connect to the base so as to fully fill the sensor guard.

The devices provided herein are compatible with a range of sensors,including sensors that measure conductivity, dissolved oxygen (DO),oxygen-reduction potential (ORP), pH, pressure, depth, level, turbidity,ion selective electrodes for various ions, such as nitrate, ammonium andchloride, temperature.

“Continuous distal sensing surface” refers to a plurality of independentsensors that are placed adjacent to each other to form a single surfacethat, to the naked eye or casual observer, appears continuous. Theinvention, however, does tolerate some separation distance, preferablyless than 2 mm, less than 1 mm, or less than 0.5 mm. Tight-fit andtightly held are used herein in a similar manner, to reflect the minimalspace between adjacent surfaces, in contrast to conventional systemsthat have rather large gaps and attendant large void volumes.Accordingly, adjacent distal sensing surfaces that “substantiallycontact” each other may refer to an open surface area between sensorsthat is less than 5%, or less than 1% of the surface area of thecontinuous distal sensing surface.

Unless defined otherwise, “substantially” refers to a value that iswithin at least 20%, within at least 10%, or within at least 5% of adesired or true value. Substantially, accordingly, includes a value thatmatches a desired value.

“Operably connected” refers to a configuration of elements, wherein anaction or reaction of one element affects another element, but in amanner that preserves each element's functionality. For example, a wiperoperably connected to a center support refers to the ability to move thewiper without impacting the functionality of the center support thatsupports the sensors in an interlocking configuration.

“Releasably connected” or “releasably connects” refers to aconfiguration of elements, wherein the elements can be temporarily andreliably connected to each other and, as desired, removed from eachother without adversely impacting the functionality of other elements ofthe device.

“Void volume” refers to the empty space between sensors and betweensensors and a side-wall of a cover or a sensor guard. Conventionalmulti-parameter sondes have void volumes that are relatively large withsufficient separation distances that biological growth can become asignificant problem. The low void volumes of the instant devices reflecta tight fit between all adjacent sensors and the side wall of the sensorguard, with separation distances so small that biological growth issubstantially constrained. In this aspect, “substantially constrained”refers to minimal growth that does not affect long-term sensorperformance. For example, there may be biological growth not observableto the naked eye, or the observable growth is so minor that there is nodetectable drop-off in a sensor performance. Void volume may beexpressed in terms of a fraction or percentage of guard's sensorreceiving volume.

In contrast, “sample volume” or “sensor volume” refers to that part ofthe system in which fluid is desirably located, such as for waterparameter measure or sensor storage. In an aspect, this volume isbetween about 20 mL and 100 mL, or about 40 mL to 50 mL, depending onsensor size, for example. In comparison, conventional sondes may have upto around double, triple or an order of magnitude volumes, as a resultof the substantially large void volume that requires filling so as toensure the distal sensing surfaces are covered with liquid.

Example 1 Multi-Parameter Sonde

A multi-parameter sonde may have pie shaped sensors that fill the entiresensor space of the multi-parameter sonde. Other sondes, in contrast,use mostly round sensors that have open space between sensors.

The pie shape reduces the volume of liquid that surrounds the sensorwhich has a certain advantages. First, a small volume of water in a flowcell leads to faster testing results during low flow sampling, such asfrom well water. Second, less calibration solution is required tocalibrate and instrument, which can save significant amount of money assome calibration fluids cost several hundred dollars a liter.

In addition, pie shaped sensors are easier to clean after longdeployments because the sensors are in direct contact with each other,which reduces the surface area in direct contact with biologicallyactive water that grow algae and other biological growth. Othermulti-parameter sondes have sensors that are spread out and thebiological growth has to be cleaned in between sensors. The sondesprovided herein do not require cleaning in between sensors, even afterextended periods of use, such as on the order of weeks or months.

Referring to FIG. 1A-1C, in a fully assembled configuration ready forsensing in a submerged environment, the multi-parameter sonde 10 has aplurality of independent sensors 20 disposed within a sensor guard 170.The sonde is shown in a sensor guard configuration 178 in that thesensing end 173 having a plurality of fluid openings 174 is aligned withthe distal sensing surfaces 30 of sensors 20. Covering end 175 ispositioned in a proximal position, relative to the sensing end 173 ofthe sensor guard. The sensing end corresponds to the sample volume. Thesensor guard is open-ended, with one end, the proximal end, closed viathe connection with the base 50 and the other end, the distal end,closed via the cap 177. Sensor receiving volume 280 corresponds to theportion of the sensor guard 170 in which the sensors extend and,therefore, depends on the sensor longitudinal length. The volume ofsensing volume 173 may be about 40 mL-50 mL, or about 46 mL.

The base 50 may further comprise a display portion 52 for indicatingsonde and sensor status, and a base end 54 for containing other sondecomponents, such as power supply, electronics and external connectionport 53.

A multi-parameter sonde with the sensor guard 170 removed is illustratedin FIG. 2A-2B. Plurality of independent sensors 20 (20 a 20 b 20 c 20 d)(shown as sensor blank 160)) each have a distal sensing surface 30 and aproximal end 40 connected to the base 50. As shown in FIG. 2B, adjacentdistal sensing surfaces contact each other to form a continuous distalsensing surface 60 having a substantially planar surface. The fittingbetween the independent sensors is so tight, that the outer surfacecross-section visually appears as a solid circle. Because the fitbetween all the adjacent sensors is close or tight, the sensors are alsoreferred herein as having a high “form factor”, with minimal void volumeor dead space between the sensors that extend from the base 50 andproximal end 40 to the distal sensing surface 30 and, in combination,the continuous distal sensing surface 60, as discussed further inExample 2. Also illustrated is a wiper 180 that is connected to a distalend 181 of a drive shaft 182. Various dimensions are illustrated withelement numbers 21 22 23, with respect to air-pocket formation duringuse. When sensor guard 170 is in place and the sonde is inserted intoliquid water, with distal sensing surface or end 30 in a downwardorientation, an air pocket forms between the outer sensor 20 surfacesand a corresponding inner facing sensor guard surface. The air pocketmay correspond to the longitudinal dimension 21, where no biologicalgrowth is observable, with a wetted surface corresponding to 22, wherebiological growth may occur, given that wetted region is in watercontact. The wetted to non-wetted area or length, may be expressed as aratio of dimension 22 to 21 (optionally plus 22) or 22 to 23. That ratiomay be less than 10%, less than 5% or less than 1%. A wetted region thatis confined to within at least 5% of a sensor longitudinal length fromthe distal sensing surface, accordingly, can correspond generally todimension 22 divided by dimension 23. In this context “observable” mayrefer to whether or not biological growth is seen by the naked eye. Thisreflects that any growth that is not pronounced and observable to theuser, such as microscopic-scale growth, will have minimal to no impacton the sensor operation and, therefore, on the cleanability duringmaintenance.

Example 2 High Form Factor Sensor

The sensors may generally be described as “pie shaped”, and can have aninterlocking feature that holds the sensors together. The interlockingfeature can be a tongue and grove design that holds all the sensors tothe center support that is operably connected to the wiper. This has anumber of benefits, including enhancing impact resistance as theinterlocking protects the sensors during a drop or impact in situationswhere the sensor guard is not installed. It also holds the sensorstightly together and makes sensor guard installation easier. Without theinterlocking feature the sensors tend to splay out and have to be pushedtogether to install the tightly fitting sensor guard.

FIGS. 3A-3J are various views of an independent sensor 20. Depending onthe sensor type, and more specifically the liquid parameter beingmeasured, the sensor surface 30 will have different sensing elements.There is, however, other common aspects, to the sensors. For example, acorner edge 70, also referred herein as an inner corner edge 70, definesan inward facing orientation of the sensor relative to the sonde centeraxis. A pair of side surfaces 80 extend from corner edge 70 and end atouter edge 90. The pair of side surfaces 80 are separated from eachother by side angle 100 defined as the angle between the planes formedby side surfaces 80 (see, e.g., FIG. 3F). Outer-facing surface 110extends between the outer edges 90 of the side surface 80, therebyforming a three-sided housing for the sensor, as illustrated in FIGS. 3Fand 3J.

For aspects where the distal sensor surfaces have excess space betweenadjacent edges, a distal insert surface or spacer may be provided totraverse the excess space, thereby functionally providing a continuousdistal sensing surface.

The sensors may be provided with an interlocking mechanism. Referringspecifically to FIG. 3G, the sensor may have a top portion 81 with a topwidth 82 and a bottom portion 83 with a bottom width 84. The bottomwidth 84 is less than the top width 82, thereby forming a bottom notch85 and notch end surface 86. A tongue 87 extends from the notch endsurface 86 in longitudinal direction that aligns with the sensorhousing. Fastening member 88 in the sensor proximal end may be used tofasten the sensor to the base, including to provide an electricalconnection to the base.

Referring also to FIGS. 8-11, sensors with corner groove 72 of eachsensor in a combination of sensors form a central orifice 300 in whichdrive shaft 182 extends therethrough. The drive shaft rotates wiper 180which is connected thereto. For additional clarity, FIG. 9 illustratesone of the sensors removed to reveal drive shaft 180 and central support200, which are not fully visible in the sensor assembled configurationof FIG. 8. Because central support 200 has a larger width than the driveshaft 180, the bottom portion of the sensor has a larger cut-out thanthe top portion groove. The central support has a plurality of grooves320 configured to receive from each sensor tongue 87, thereby providingtight contact with the sensors to facilitate placement of sensor guardover the sensors' outer-facing surfaces. Longitudinal direction, unlessindicated specifically otherwise, is reflected by arrow 11 in FIG. 8.

The independent sensors may be further defined in terms of alongitudinal distance 340 (FIG. 3H) and a radial dimension 342 (FIG.3F).

The high-form factor sensors may also be described as pie-shaped,referring to a shape of the sensor cross-section having a corner withtwo-sides, and a curved outer surface. FIG. 18 shows an embodiment wherethe side angle 100 at corner edge 70 (for clarity, corner groove 72 isnot illustrated) that defines the angle between sides 80 of a sensorsare 90°, so that four sensors are used in the sonde to provide acylindrically-shaped high form factor sensor package. This pie-shape,formed by side walls 80 and outer wall 110, besides having benefit ofbeing able to be tightly packed, also provides increased sensitivity,such as for optical-based sensors. A pie shaped sensor 1800 has anincreased surface area of 45% compared to an equivalently sized circularshaped sensor 1810, as indicated in FIG. 18. This permits opticalspacing increase between emitting 1820 and receiving 1830 optics to beincreased in the pie sensor by about 89% (compare separation distance1840 with 1850) compared to conventional circular-shaped sensors, withattendant increase in sensitivity.

Example 3 Sensor Base

Referring to FIGS. 4A-4B, the sensor base 50 is shown without the sensorguard, the sensors, or the central support. Sensor ports 51 areconfigured to receive a proximal portion of the sensors, including afastening member 88 shown in FIG. 3G. In the illustrated embodiment,four ports are shown for receiving four independent sensors, or acombination of sensors and sensor blanks having the same shape of thesensor. The blank sensor is useful for embodiments where not all sensorsare needed and that, instead of occupying the space with an unusedsensor, a relatively cheap blank may be used so as to maintain the manyadvantages described herein. Central support port 52 may be used tooperably connect central support and attendant drive shaft extendingtherefrom. The port connections provide a reliable connection in amanner that also ensures convenient removability. Sensor base maycontain other components for sonde functionality, operability andcontrol, including such as by connector 53 for connection to an externalelectronic device.

Example 4 Reversible Sensor Guard

The reversible sensor guard 170 is shown in FIG. 1A-1C in a sensor guardconfiguration 178 and in FIG. 5A-5B in a sensor storage configuration179. These different configurations reflect a unique aspect of theinstant sondes, namely that the storage cup is an integral part of thesystem. This avoids the risk of a user forgetting a storage cup in thefield, with an attendant risk of permanent sensor damage associated withsensor drying. In the stored configuration 179, the openings 174 areproximally positioned adjacent to the base 50 (FIG. 5A). In contrast, ina sensor guard configuration 178, the passages 174 are positioneddistally and adjacent to the sensing surface to facilitate fluidintroduction to the sensor surface while still protecting the sensorsfrom unwanted physical contact (FIG. 1A-1C).

FIG. 5C is a sectional view along a central plane of the distal end ofthe sensors 20 to the sensor guard cap 177 of sensor guard 170. Aninternal surface 270 of sensor guard cap 177 faces the distal sensingsurface 60, and is separated by a sample distance 271. In the storageconfiguration 179 of FIGS. 5A-5B, the sample distance forms a storagevolume for receiving a liquid to ensure sensors 20 remain wetted toavoid sensor damage, such as during when the sonde is removed from aliquid environment. Accordingly, storage volume is configured to beliquid tight with respect to the surrounding environment. In contrast,for a sensor guard configuration 178 (illustrated in FIG. 1A-1C), thesample distance 271 forms a corresponding sensing volume, but that is,of course, not liquid-tight to the surrounding environment, such as dueto the presence of fluid opening(s) 174. In this manner, a singlecomponent can serve two different functions depending on orientation:(1) sensor protection during liquid sensing; and (2) sensor storage witha liquid that is maintained in liquid contact with the distal surface60. This avoids the need, as required in conventional sondes, ofcarrying a separate cap element. This all-in-one integrated approach isillustrated further in FIG. 14.

FIG. 14 summarizes the steps used to switch between a sensor guardconfiguration 178 (top panel) and a stored configuration 179 (bottompanel). In step 1500 the sensor guard is removed from the base. The capis removed from the sensor guard in step 1510. The sensor guard isrotated 1520 so as to move the plurality of fluid openings from a distalposition to a proximal position. In step 1530 the cap is reinstalled(now at the other end of the sensor guard). The sensor guard is attachedto the base in 1540.

A close-up view of the sensor guard 170 provided in sensor guardconfiguration 178 is illustrated in FIG. 15. Also shown is the distalsensing surface 60 formed from the sensors, including the visiblesensors 20 a 20 b 20 c, wiper 180, cap 177 and passage 174. FIG. 15 alsoillustrates the various tight fits such as between sensor guard 170inner facing surface 171 and sensor 20 c outer surface 110 c. Also,there is a tight fit between adjacent sensor side walls, with adjacentsensors 20 b and 20 c having side walls 80 b and 80 c, having atight-fit. Although the tight-fit is so close that there is no readilyobservable gap, the tight-fit need not be liquid-tight. Some liquid isexpected to leak between sensors, such as less than 10 mL, or less thanabout 1 mL. However, the separation distance between adjacent sensorsand the outer sensor surface is so small, such as less than 1 mm or 0.5mm, that there is minimal void volume and biological growth therein issubstantially constrained and avoided. The cap may be threaded so as tomate with corresponding threads on either end of the sensor guard 170.

FIGS. 6A-6D, for additional clarity, illustrate a sensor guard removedfrom the sonde. FIGS. 6B-6C illustrate a plurality of individualpassages 174, whereas FIGS. 6A and 6D illustrates each of the individualpassages comprising a plurality of passages, in this example two pairedpassages 198 separated by a separation distance 199. In other words,each of the passages or openings 174 illustrated in FIG. 6B can be splitinto multiple passages, such as the two passages 198 of FIG. 6D. Use ofpassages comprising a plurality, such as two individual paired passagesseparated by a separation distance, can provide improved lightcharacteristics for sensors that provide an output signal based on alight characteristic. The configuration depicted in FIGS. 6A and 6Densures that irrespective of a light direction or guard orientation, abackground light intensity is relatively constant, thereby improvingsensor sensitivity, as further explained in U.S. Pat. App. 62/115,593.

Example 5 Wipers

The instant single continuous sensing surface allows a sensor cleaningbrush to wipe on a flat even surface, without open spaces betweensensors. The brushes and wipers are more effective at cleaning becausethere is not deflection around the sensors due to the space betweenprobes, as is currently found with conventional multi-parameter sondeson the market.

FIG. 7A-7D are views of a wiper 180 detached from the sonde, morespecifically from a drive shaft of the sonde. The wiper may have acentral body 183 with a lower surface 184 (FIG. 7C) and an upper surface185 (FIG. 7A). A first wiper 186 and a second wiper 187 may connect toopposite surfaces for cleaning a distal sensing surface and aninward-facing surface of the sonde. In an aspect, the wipers may bebrushes. The brushes may be configured to provide maximum cleaning area,with the brushes that clean the distal sensing surface cleaning asmaller overall area due to the presence of a drive shaft 182terminating in a distal end 181 that is receivably positioned in areceiving passage 191 on the wiper 180.

FIGS. 12-13 are a close-up view of the wiper installed configuration anda wiper removed configuration. FIG. 16 shows an end-on view of the wiper180 and distal surfaces of a four-sensor embodiment, illustrated assensors 20 a 20 b 20 c 20 d. Also illustrated is the tight fit betweenthe sensor guard 170 and sensor outer facing surfaces 110 a 110 b 110 c110 d. Side surfaces of adjacent surfaces are also in a tight-fitconfiguration, as called out by surfaces 80 a 80 b. In addition, thesonde has the capability to move the wiper brush 180° from the sensor itis currently reading. The sonde electronically detects the location ofeach probe installed from a unique resistor installed in the sensor. Forsensors that are sensitive to the wiper brush's proximity, the brushmoves to the opposite side during its measurement.

FIG. 17 is a schematic illustration of the various components andrelated geometry associated with turning a drive shaft to turn thewiper, including a motor 188, slip-clutch 189 and drive shaft 182. Theparts required to move the drive shaft may be positioned within acentral support, to which the plurality of sensors is connected. Theslip-clutch is an important component that provides a number offunctional benefits. For example, during sonde sensor handling andreplacement, the brush is typically moved and without such a slip-clutchis vulnerable to breakage with attendant costly repair. The slip-clutch,accordingly, provides improved sonde sensor maintenance and repair, witha user simply moving the brush in any direction to facilitate access tothe desired sensor.

Statements Regarding Incorporation by Reference and Variations

All references throughout this application, for example patent documentsincluding issued or granted patents or equivalents; patent applicationpublications; and non-patent literature documents or other sourcematerial; are hereby incorporated by reference herein in theirentireties, as though individually incorporated by reference, to theextent each reference is at least partially not inconsistent with thedisclosure in this application (for example, a reference that ispartially inconsistent is incorporated by reference except for thepartially inconsistent portion of the reference).

The terms and expressions which have been employed herein are used asterms of description and not of limitation, and there is no intention inthe use of such terms and expressions of excluding any equivalents ofthe features shown and described or portions thereof, but it isrecognized that various modifications are possible within the scope ofthe invention claimed. Thus, it should be understood that although thepresent invention has been specifically disclosed by preferredembodiments, exemplary embodiments and optional features, modificationand variation of the concepts herein disclosed may be resorted to bythose skilled in the art, and that such modifications and variations areconsidered to be within the scope of this invention as defined by theappended claims. The specific embodiments provided herein are examplesof useful embodiments of the present invention and it will be apparentto one skilled in the art that the present invention may be carried outusing a large number of variations of the devices, device components,methods steps set forth in the present description. As will be obviousto one of skill in the art, methods and devices useful for the presentmethods can include a large number of optional composition andprocessing elements and steps.

When a group of substituents is disclosed herein, it is understood thatall individual members of that group and all subgroups, are disclosedseparately. When a Markush group or other grouping is used herein, allindividual members of the group and all combinations and subcombinationspossible of the group are intended to be individually included in thedisclosure.

Every combination of elements described or exemplified herein can beused to practice the invention, unless otherwise stated.

Whenever a range is given in the specification, for example, a sizerange, an angle range, or a time or a number range, all intermediateranges and subranges, as well as all individual values included in theranges given are intended to be included in the disclosure. It will beunderstood that any subranges or individual values in a range orsubrange that are included in the description herein can be excludedfrom the claims herein.

All patents and publications mentioned in the specification areindicative of the levels of skill of those skilled in the art to whichthe invention pertains. References cited herein are incorporated byreference herein in their entirety to indicate the state of the art asof their publication or filing date and it is intended that thisinformation can be employed herein, if needed, to exclude specificembodiments that are in the prior art. For example, when composition ofmatter are claimed, it should be understood that compounds known andavailable in the art prior to Applicant's invention, including compoundsfor which an enabling disclosure is provided in the references citedherein, are not intended to be included in the composition of matterclaims herein.

As used herein, “comprising” is synonymous with “including,”“containing,” or “characterized by,” and is inclusive or open-ended anddoes not exclude additional, unrecited elements or method steps. As usedherein, “consisting of” excludes any element, step, or ingredient notspecified in the claim element. As used herein, “consisting essentiallyof” does not exclude materials or steps that do not materially affectthe basic and novel characteristics of the claim. In each instanceherein any of the terms “comprising”, “consisting essentially of” and“consisting of” may be replaced with either of the other two terms. Theinvention illustratively described herein suitably may be practiced inthe absence of any element or elements, limitation or limitations whichis not specifically disclosed herein.

One of ordinary skill in the art will appreciate that materials andmethods other than those specifically exemplified can be employed in thepractice of the invention without resort to undue experimentation. Allart-known functional equivalents, of any such materials and methods areintended to be included in this invention. The terms and expressionswhich have been employed are used as terms of description and not oflimitation, and there is no intention that in the use of such terms andexpressions of excluding any equivalents of the features shown anddescribed or portions thereof, but it is recognized that variousmodifications are possible within the scope of the invention claimed.Thus, it should be understood that although the present invention hasbeen specifically disclosed by preferred embodiments and optionalfeatures, modification and variation of the concepts herein disclosedmay be resorted to by those skilled in the art, and that suchmodifications and variations are considered to be within the scope ofthis invention as defined by the appended claims.

1. A multi-parameter sonde comprising: a plurality of independentsensors each having a distal sensing surface and a proximal end; and abase that operably connects to the proximal end of each of the sensors;wherein adjacent distal sensing surfaces substantially contact eachother to form a continuous distal sensing surface comprising theplurality of independent sensors.
 2. The multi-parameter sonde of claim1, wherein each of the plurality of independent sensors comprise: aninner corner edge; a pair of side surfaces extending from the innercorner edge and ending at an outer edge, wherein the side surfacesdefine a plane and the planes are separated from each other by a sideangle; and an outer facing surface that connects the pair of sidesurfaces at the outer edge, thereby forming a three-sided sensorhousing; wherein in use the side surfaces of adjacent sensors are insubstantially continuous contact.
 3. The multi-parameter sonde of claim2, wherein the plurality of sensors form an outer surface having acircular cross-section.
 4. The multi-parameter sonde of claim 2, whereinthe base operably connects between 2 and 12 sensors and the side angleis independently selected from a range that is greater than or equal to30° and less than or equal to 180°.
 5. The multi-parameter sonde ofclaim 4, wherein the base operably connects four sensors, each sensorhaving a side angle of 90° and an outer facing surface with a curvaturecorresponding to one-quarter of a circle so that the plurality ofsensors form an outer surface with a cross-section that is substantiallycircular.
 6. The multi-parameter sonde of claim 5, wherein at least oneof the sensors comprises a sensor blank having an external shape thatcorresponds to an external shape of one of the sensors.
 7. Themulti-parameter sonde of claim 2, further comprising a sensor-guardhaving a sensor receiving volume and a sample sensing volume, whereinthe plurality of sensors occupy substantially the entire volume of thesensor receiving volume.
 8. (canceled)
 9. The multi-parameter sonde ofclaim 1, further comprising a central support extending from the basethat independently releasably connects each of the plurality of sensors.10. The multi-parameter sonde of claim 9, wherein each of the pluralityof sensors comprises: a corner edge extending from the distal sensingsurface and partway toward the proximal end, the corner edge shaped toreceive at least a portion of the central support or a drive shaftextending therefrom; a pair of side surfaces that extend from the corneredge and that are separated from each other by a side angle; and anouter facing surface that connects the pair of side surfaces at an outeredge of each of the side surfaces, thereby forming a three-sided sensorhousing.
 11. The multi-parameter sonde of claim 10, wherein each of theplurality of sensors further comprise: a top portion of each of the pairof side surfaces having a top width; a bottom portion of each of thepair of side surfaces having a bottom width, wherein the bottom width isless than the top width to thereby form a bottom notch and a notch endsurface; a tongue connected to the notch end surface and longitudinallyextending partway down the notch; a fastening member to fasten thesensor to the base; wherein in combination, the plurality of sensorsform: a top sensing volume having a central orifice for receiving adrive-shaft extending from the central support; and a bottom portionhaving a central receiving volume for receiving the central support anda drive shaft motor positioned therein; the central support having aplurality of grooves to operably receive the tongues and independentlysecure each of the sensors to the central portion.
 12. Themulti-parameter sonde of claim 11, wherein each of the plurality ofsensors are tightly held against the central shaft, and a sensor guardis tight-fitted around an outer edge formed by the outer-facing surfacesof the sensors.
 13. The multi-parameter sonde of claim 12, wherein theouter-facing surface is curved so that the plurality of sensors incombination form a circular cross-section.
 14. The multi-parameter sondeof claim 12, wherein the plurality of sensors form a continuousouter-facing surface that is in a tight fit with an inner-facing surfaceof the sensor guard.
 15. The multi-parameter sonde of claim 12, whereina sensor side wall is in continuous contact with an adjacent sensor sidewall, and wherein each of the sensors: extend a longitudinal distancethat is greater than or equal to 5 cm and less than or equal to 50 cm;have a radial dimension that is greater than or equal to 1 cm and lessthan or equal to 10 cm; and in combination have a void volume that isless than or equal to 75 mL, wherein the void volume comprises at leastone dimension associated with a sensor that is sufficiently small thatbiological growth is substantially constrained.
 16. (canceled) 17.(canceled)
 18. The multi-parameter sonde of claim 11, further comprisinga wiper connected to a distal end of the drive shaft for rotablybrushing each of the distal sensing surfaces.
 19. The multi-parametersonde of claim 18, further comprising a sensor guard that connects tothe base and surrounds the plurality of sensors in a tight-fitconfiguration, the sensor guard having a sample sensing volume formed bya distal portion of a sensor guard sidewall, a sensor guard top surface,and the plurality of distal sensing surfaces, wherein the wiper ispositioned within the sample sensing volume; and wherein the wipercomprises: a central wiper body connected to the drive shaft, thecentral wiper body having a lower surface that faces the distal sensingsurfaces and an upper surface that faces the sensor guard top surface; afirst wiper connected to the lower surface for cleaning the plurality ofsensing surfaces; and a second wiper connected to the upper surface forcleaning an inward-facing surface of the sensor guard top surface,wherein the first and second wipers each comprise a brush. 20.(canceled)
 21. (canceled)
 22. The multi-parameter sonde of claim 19,further comprising a motor and a slip clutch operably positioned in thecentral support and connected to the drive shaft to provide rotationalmotion of the drive shaft and the wiper connected thereto.
 23. Themulti-parameter sonde of claim 22, further comprising a position sensoroperably connected to the motor to ensure wiper storage at a wiperstored position that does not adversely affect a sensor function,wherein the wiper storage position is at a position that is 180° from asensor that is actively measuring a parameter.
 24. (canceled)
 25. Themulti-parameter sonde of claim 1, further comprising a sensor guard thatsurrounds the plurality of sensors and connects to the base, wherein thesensor guard has: a sensing end comprising a fluid opening; a coveringend that is liquid tight; a cap configured to connect to both thesensing end and the covering end; wherein the sensor guard is reversiblyconnected to the base to provide: a sensor guard configuration for thesensing end aligned with the distal sensing surfaces and the coveringend connected to the base; and a sensor storage configuration for thecovering end aligned with the distal sensing surfaces and the sensingend connected to the base; wherein the sensor guard is configured toreversibly change between the sensor guard configuration and the sensorstorage configuration.
 26. (canceled)
 27. The multi-parameter sonde ofclaim 25, wherein the cap has an internal surface that opposably facesthe continuous sensing distal sensing surface and is separated from thecontinuous sensing distal sensing surface by a sample distance that isgreater than or equal to 1 cm and less than or equal to 10 cm, themulti-parameter sonde further comprising: a rotatable brush thattraverses the sample distance for simultaneous cleaning of thecontinuous sensing distal surface and the cap internal surface. 28.(canceled)
 29. The multi-parameter sonde of claim 25, wherein duringimmersion in water, an air pocket forms between an outer surface of theplurality of independent sensors and an inner surface of the guard,wherein no observable biological growth occurs on any sensor or guardcontact surface in contact with the air pocket, wherein each sensor hasa wetted region that is confined to within 5% of a sensor longitudinallength from the distal sensing surface.
 30. (canceled)
 31. Themulti-parameter sonde of claim 1, further comprising: a reversiblesensor guard comprising: a sensing end comprising a fluid opening; acovering end that is liquid tight; a cap that connects to either of thesensing end or the covering end; wherein the reversible sensor guard isreversibly connected to the base to provide: a sensor guardconfiguration for the sensing end aligned with the distal sensingsurfaces and the covering end connected to the base; and a sensorstorage configuration for the covering end aligned with the distalsensing surfaces and the sensing end connected to the base; and whereinthe sensor guard is configured to reversibly change between the sensorguard configuration and the sensor storage configuration.
 32. Themulti-parameter sonde of claim 1, wherein adjacent sensors are separatedfrom each other by an average separation distance that is less than 0.3mm.
 33. A sensor configured for use in a multi-parameter sonde, thesensor comprising: an inner corner edge; a pair of side surfacesextending from the inner corner edge and ending at an outer edge,wherein the side surfaces define a plane and the planes are separatedfrom each other by a side angle that is greater than 30° and less thanor equal to 180°; an outer facing surface that connects the pair of sidesurfaces at the outer edge, thereby forming a three-sided sensorhousing; a distal sensing surface; a proximal end, wherein the pair ofside surfaces and the outer-facing surface longitudinally extend betweenthe proximal and the distal sensing surface to form a sensor housing;and a sensor disposed within the sensor housing and having an activesensing end positioned at the distal sensing surface.
 34. (canceled) 35.The sensor of claim 33, further comprising a top portion of each of thepair of sides having a top width; a bottom portion of each of the pairof sides having a bottom width, wherein the bottom width is less thanthe top width to thereby form a bottom notch and a notch end surfacebetween the top portion and the bottom portion; a tongue connected tothe notch end surface and longitudinally extending partway down thenotch; and a fastening member connected to the proximal end for operablyconnecting the sensor to a multi-parameter sonde.
 36. (canceled) 37.(canceled)
 38. A method of monitoring one or more water parameters, themethod comprising the steps of: immersing the multi-parameter sonde ofclaim 31 into water, wherein the multi-parameter sonde is in the sensorguard configuration and the multi-parameter sonde is positioned in adirection with the distal end furthest from a surface of the water;forming an air-pocket between an outer-facing surface of the sensors andan inner-facing surface of the guard, wherein the air-pocket forms over90% or greater of a longitudinal distance of the sensors extending fromthe base, and less than 10% of the longitudinal distance from the distalsensing end is wetted; and wherein observable biological growth isprevented in the air pocket and is confined to a biological growth areacorresponding to the wetted distal sensor end.